Data networks today mostly rely on packet switching technology where data signals are transmitted in the form of data packets, each containing a header with a destination address. Data packets are forwarded through the network from node to node until they reach their ultimate destination. A process referred to as routing directs packet forwarding based on the destination address contained in each data packet and locally stored routing information. The most common protocol in packet switched networks is known as the Internet Protocol (IP).
Since packets travel hop-by-hop towards their destination, every intermediate packet node or router has to process the packet header of each data packet to determine the routing. This is inefficient, causes delay at each router and contributes to high power consumption and equipment costs.
Often, IP routers use optical networks as underlying network technology for their interconnections at wide area. Optical networks forward data signals at much lower costs, both in terms of CAPEX and or OPEX. It is therefore desirable, to do as much forwarding in the optical layer as possible and avoid unnecessary header processing.
The article “Optical IP Switching for dynamic traffic engineering in next-generation optical networks” by M. Ruffini et al, proceedings of the 11th International Conference on Optical Networking Design and Modeling—ONDM 2007, pp. 309-318, describes a method to bypass routing when possible by dynamically creating an optical cut-through between adjacent optical nodes when the data examined between its upstream neighbor and its downstream neighbor is over a pre-established path threshold.